Corner locking construction for paperboard containers



R. E. ACKER' Sept. 15, 1953 CORNER LOCKING CONSTRUCTION FOR PAPERBOARD CONTAINERS Original Filed Nov. 29, 1947 Patented Sept. 15, 1953 LOCKING CONSTRUCTION Fon. raramsosnu CONTAINERS Ralph: E; Ackerifl Font Worth; Tex., assignon to- GontainerzGorporation ofAmerica; (lhicazmlllg,

a corporationlottDelawarer applicationNovemlier '29; I947, Serial Noz" 8381K; Divided and thimapplication January seria -nu.- 137.1901- This inventiom relates; in at paperboard, con; tainer. of the. tray." type: adapted; to; be: readily erected, from a; blank: and; provided; with corner ock meansl which. locla the walls. in container forming relation upon; positioning; of the. walls inerected. conditionz. Monezparticularly; the. invention relates. to; a. corner lbckine nstruction for. a paperboard: container: automatically effec tive upon settingnrn oflthecontalnera Briefly and; generally the invention; is embodied in a container: havinglockingp tabson opposite ends of: eachxof onepair-ofzwallimembers, and slits betweena adjacent: wall members in which the. tabs. locklngly; engage: to] retain; the several wall members; in: desired; trihedralrela: tion to form the;corners=of thezcontainer; The principle of the invention. isaapplicabl'e; to many types of containersawithw.walltmemberszim various relations to each-other;

It is an object-of the inventiom to. provide a paperboard container'in whichtheends off ad.- jacent Wall elements; are lockedi in set: up. posi;- tion by cooperating loclt'ing" means operable simply by movement of the wall elements into position. It is another object to provide a cor.- ner locking constructionQfor-a paperboard container which is eflective automatically upon movement of the container: wall members": to erected position to look said members: in the erected position. It is also an object to provide a corner lock constructiomfor alpaperboard con tainer which will automatically lock the wall members of the container desired trihedral relation. A further object is to providea corner lock arrangement for rectangular containers which will retain the: walls lit-desired squared relation; Still another object is" the provision of a container-in whichadjacent wall elements are providedwith cooperablelocking-means at their contiguous portionsin such' relation that they coact. to lock the" wall elementsin=prede= termined erected positionautomatically upon movement of j the; wallv elements-rte saidposition; A still further object of'the inventibnds to pro vide a blankwhich may readily-be folded to form a container with such' corner lqckinefconstrucition.

Other and further old1 ects and'TGaWres-off'the invention willbe' apparent. to: thoseskilled in the art from the following description-and the-ap pended drawin s; which form a part thereof Fig. 1 is'a plan of' wblank for'an embodiment of my invention; and

Fig; 2 is' a perspective view of onee'nd of" a container-formed -from-the showman-Fig: 1.

Referring. to. Figs.v 1., and. 2}. the invention is illustrated as; embodied/in a tray suitable for packaging tomatoes. and; other. products. The blank-.5.0:as shownin Fig, Loomprises a suitable sheet with. longitudinal... parallel score lines 5| and. transverse parallel score lines 52 defining a. substantially rectangular bottom panel 53. Side wall. panels 54 and: end wan panels'55 are connected to the-bottom panel-along the lines 51 and. 52, respectively. End cover flaps 5 6 are hingedly connectedto the end wall panels 55 along hinge lines 51, althoughthese cover flaps may be omitted if desired. Locking tabs 58 are hingedon. the end edgesof the end wall panels 55 along lines:59. These hinge'lines 59 extend at substantially-right.anglesito the-lines 52, and are ofisetinwardlywelative. to. the lines 5| a distance substantiallyequal. to twice the thickness of the. material: employed for. the blank. The tab 58-iis divided fromthe side wall panel54 by a cut 60, substantially; aligned with theline 52. The ends of thiscut preferably are curved to extend inwardly. relativeto the line.52 a distance substantially, equal to one thickness of the material. A cut 61, preferably alignedwith the line 5;l,,extends fromthet'marg-in of the blank to the outer end of the tab 58, and a notching cut 62 extends from thel-inner endrof thecut 6| to the outer: end. of the hinge line 59. This cut 62 serves:v to providev anotch. in the: tab when the blank isrfolded .on the line' 59.

An endfiap. 63 1s: hingedato aportion of the adjacentend edgeiofthecsiderwall panel 54 along a line, a portionof: the. edgeof the flapv 63 in alignment withathe line 64 being separated from an adjacent portion of the panel 54 by a slit 65L. The slit t5 -extends outwardly from the outer end of thecut 50 the-inner end of the hinge line 64; and both the slit 65' andline 64 are ofiset inwardly otthezline 52 a. distance corresponding-to the thickness of the material. The oblique line-of cut at theouter end portion of out 60, which merges-into the cut 55, forms a slanting edge portion' on-flap fi3' that provides a;- flared opening'leadi'ng'to the slit 65 and is adapted to receive the advancing' edge of tab 58 and facilitate its subsequent entranceinto the slit 65 when the-flap' fii is disposed at'an angle to its attached wall 54.

The cut 60,- being-aligned'with the line 52*and ofiset from the slit 5 andhinge line 64-; forms an-end edge portionon the sidewall 54'which extends outwardly beyond the hinge line 64. Thus when tl refl'ap fii is' swung on its-hinge line 7 to assumea; position' substantiallyat a right were where it merges into slit 65, provides one of the T sides of the flared opening-the other side vof such opening being provided by the end of the side wall 54. The cut 6| separates the flap 63 from the end wall panel 55, and a cut 66 extends from the junction of the cuts 6| and 62 to the cut 60 to separate the flap 63 from the tab 58. The cut 66 is arcuate, but may be straighter otherwise curved, if desired. .The dimension of the tab 53 along the cut 60 is smaller than the perpendicular distance from the line 52 to the end of the tab defined by the junction of the lines 62 and 66, and the" closed outer end of the slit 65 is at a point spaced perpendicularly from the hinge line 59 a distance no greater, and preferably less, than the distance from the line 52 to the tab end defined by the lines 62 and 66. A slit 67 is provided in each end wall panel 55 along a line corresponding to the upper edges of the pair of flaps 69 at each end when the blank is erected in container form. As illustrated, this slit 61 is in the shape of a'shallow V, since the flaps are shown as so cut that when erected their upper edges will incline downwardly and inwardly from the side walls. r V

One end of the container formed from the blank of Fig. 1 is shown inFig. 2. The container may be easily set up'by folding the various elements shown and described. The flaps 53 may first be bent upwardly perpendicular to the side panels 54, along the hinge connections described, and the side panels 54 arethen bent upwardly along the lines 51 into perpendicular relation to the bottom panel 53, as shown in Fig. 2. As will be clear from the drawing, this positioning of the side panels 54 brings the end flaps 63 into position between the panels at each end in a plane substantially parallel tothe plane of the end wall panel 65' when the latter is movedto set up position.

The tabs 58 are then bent along their hinge lines 59 into substantially perpendicular relation with the end wall panels 55, and the panels .55 swung upwardly on the lines 52, with the tabs 58 engaging the inner surfaces of the side wall panels 54. The described offsetting of thehinge lines 59 facilitates this positioning of the tabs relative to the side wall panels, as well as their. subsequent movement to locking position.

As movement of the panels 55 to the perpendicular position continues, the tabs 58 engage in the slits 65, and due to the greater dimension of the tabs along its hinge line and the formation of the slit 65 sothat its closed end is substantially the same distance from the adjacent corner of the bottom panel 53 as the notching cut 62, the engagement of the tab increases until locking action occurs when the panel 55 reaches its position perpendicular to the bottom anel 55. A rearwardlydire'cted edge or shoulder 68 is provided in each tab 58 by the cut 62 upon folding of the tab on the line 59, this shoulder engaging with the inner end of the hinge line 65, and the adjacent end portion of the tab engaging in the slit 65. The upper edge of the slit 6? provides a shallow tongue which is deflected inwardly of the container for frictionally engaging the upper edg s f eendfla s. 63. hu .p qvid ne. a

tional means for maintaining the flaps in their abutting relation. Instead of the slit 6! being located in the end wall to engage the upper edges of the flaps 63, it could be provided in the form of an inverted V at thebottom of the end wall centrally of the lower edge thereof so that portions of the edges of the flaps 63 Would extend into the slit to be frictionally retained in position thereby. After the container has been erected as shown in'Fig'f2, it may be filled with tomatoes or other articles and the flap 56 bent inwardly on the line 51; to asubstantially horizontal position. A sheet of transparent material may then be used to covert-he top of the container. Of course, other covering means may be employed,

, or no cover provided, as desired.

. When the container is set up, the offsetting of v the hinge lines 64 of the end flaps inwardly relative to the cut 69 by one thickness of the material permits the end flaps 63 to lie against the inner surface ofthe end walls 55 without bending or distortion thereof, and positions the edge portion of the side wall.54 defined by the cut 66 in the plane of the outer surface of the end wall 55. A similar result would be achieved asto the locking tabs 58 by offsetting the tab hinge lines 59 a distance equal to one thickness of the paperboard inwardly of the cut SI and lines 5i. For greater ease of insertion of the tabs into the interior of: the container. and into engagement with the slits 65, however, these hinge lines 59 are preferably oifsetlby twice the thickness of the material. This alsoallows for spreading of the material at the trihedral corners of the container resulting from bending of the adjacent members. Although the double thickness ofi'set theoretically prevents an. absolutely square cornor, as a practical matter a square corner is provided because, while the upper portion of the end of the side wall may be held somewhat inwardly of the bottom. portion, thebottom portion is in the vertical line of the edge portion of the end wall defined by the cut 6|.

This application is a division of my application Serial Number 788,789, filed November 29, 1947, now Patent No. 2,573,379, granted October Although the container is shown as provided with .a notch in the locking tab for maintaining the tab in lockedrelation with the other parts of the-container, under some conditions and for certain purposes 1 other: means may be employed for maintaining the tab in locking relation with the associatedslit. For example the frictional engagement between the tab and the edge portions defining the slit maybe used to hold the tab in position, particularly'where the container is to be overwrapped with cellophane or the like. In such case, the overwrapping material, once it is applied, serves as a means for maintaining the tab in position." Again, if the paperboard material is relatively compressible, as in the case of corrugated board, retention of the tab in the slit may be achieved solely by its frictional engagement therein' If the slit is so utilized to hold the tab by friction alone, the slit performs a double function in holding both wall members against moving out of their erected positions.

The lock tab: may be formed much smaller than as shown,=if desired, so as to extend from only an intermediate portion of the edge of the element to which it is hinged. The construction illustrated, however, provides a stronger corner for the container and is, therefore, preferred.

.: elthqqeh th terms sidesra i and .sii

. have been used in describing the embodiment of the invention, it will be clear that although the container is illustrated as having a rectangular bottom, and the walls as being disposed perpendicular to this bottom, the invention is applicable to other shapes of containers. For example, a six-sided container might be provided employing the corner lock construction of this invention, and similarly, a container employing this lock construction might be provided with the side walls at an angle to the bottom other than a right angle. Such adaptations of the invention to containers of various shapes will be obvious to those skilled in the art, and are clearly within the purview of this invention.

It will be obvious that various changes and modifications in the structure illustrated and described may be made without departing from the principles of the invention. Some of these possible changes and modifications have been pointed out in the foregoing description, and others will readily suggest themselves to those skilled in the art. In view of the variations which may be made in the structure employed to embody the invention, it is not intended to limit the invention to the specific embodiment illustrated and described, but only as required by the spirit and scope of the appended claims.

I claim:

1. A blank for a paperboard container comprising a paperboard sheet out and scored to provide a rectangular bottom panel, an end wall panel hingedly connected to an edge of the bottom panel, a tab hingedly connected to the end wall panel, a side wall panel hingedly connected to an adjacent edge of the bottom panel, a flap hingedly connected to the side wall along a portion of its end edge, a tab receiving cut formed in the blank extending inwardly in substantial alignment with the flap hinge line, such cut merging in a second cut extending obliquely outward of the end edge of the side wall, such second out merging in a third cut extending inwardly of the blank and offset outwardly with respect to the flap hinge line, to provide an end edge portion of the side wall extending outwardly beyond such flap hinge line whereby to form a tab guiding element to facilitate reception of the tab into the tab receivingcut, and a cut at apart of the tab hinge line remote from the bottom panel, extending inwardlyof the end wall, and providing a notch when the tab is folded on its hinge line, the notch being adapted to lockingly engage the flap at the outer end portion of the tab receiving cut when the blank is erected into container form.

2. A blank for a paperboard container comprising a paperboard sheet cut and scored to provide a rectangular bottom panel, an end wall panel hingedly connected to an edge of the bottom panel, a tab hingedly connected to the end wall panel, a side wall panel hingedly connected to an adjacent edge of the bottom panel, a, flap hingedly connected tothe side wall along a portion of its end edge, a tab receiving cut formed in the blank extending inwardly in substantial alignment with the flap hinge 1ine,,such cut merging in a second cut extending a short distance obliquely outward of the end edge of the side wall, a third cut extending inwardly of the blank substantially parallel with the flap hinge line and onset outwardly with respect thereto, to provide an end edge portion of the side wall extending outwardly beyond such flap hinge line whereby to form a tab guiding element to facilitate reception of the tab into the tab receiving cut, and a. cut at a part of the tab hinge line remote from the bottom panel, extending inwardly of the end wall, and providing a notch when the tabis folded on its hinge line, the notch being adapted to lockingly engage the flap at the outer end portion of the tab receiving cut when the blank is erected into container form;

3. A blank for a paperboard container comprising a paperboard sheet cut and scored to provide a rectangular bottom panel, an end wall panel hingedly connected to an edge of the bottom panel, a tab hingedly connected to the end wall panel, a side wall panel hingedly connected to an adjacent edgeof the bottom panel, a flap hingedly connected to the side wall along a portion of its end edge, a tab receiving cut formed in the blank extending inwardly in substantial alignment with the flap hinge line, such. tab receiving cut merging in a second cut extending obliquely outward of the end edge ofthe side wall, and defining an edge portion of the flap, such second cut merging with a third cut extending inwardly of the blank and offset outwardly of the flap hinge line, the end edge portion of the side wall adjacent the flap defined by the second and third cuts being formed to extend outwardly beyond such flap hinge line whereby to form a tab guiding element to facilitatereception of the tab into the tab receivingcut, the second, obliquely extending cut forming anv edge portion of the flap which provides, when the flap is disposed at an angle to the side wall, a flared opening between the extended side wall end edge portion and the flap edge portion adapted to receive the tab and guide it into the tab receiving cut.

4. A blank for a paperboard container comprising a paperboard sheet cut and scored to provide a rectangular bottom panel, an end wall panel hingedly connected to an edge of the bottom panel, a tab hingedly connected to the end wall panel, a side wall panel hingedly connected to an adjacent edge of the bottom panel, a flap hingedly connected to the side wall along a portion of its end edge, a tab receiving cut formed in the blank extending inwardly in substantial alignment with the flap hinge line, such tab receiving out merging in a second cut extending obliquely outward of the end edge of the side wall, and defining an edge portion of the flap, a third cut extending inwardly of the blank substantially parallel with the flap hinge line and offset outwardly with respect thereto, to provide an end edge portion of the side wall extending outwardly beyond such flap hinge line whereby to form a tab guiding element to iacilitate reception of the tab into the tab receiving cut, the second, obliquely extending cut forming an edge portion of the flap which provides, when the flap is disposed at an angle to the side wall, a flared opening between the extended side wall end edge portion and the flapedge portion ad'apted to receive the tab and guide it into the tab receiving out.

5. A blank for a paperboard container cornprising a paperboard sheet cut and scored to provide a rectangular bottom panel, an end wall panel hingedly connected to an edge of the bottom panel, atab hingedly connected to the end wall panel, a side wall panel hingedly connected to an adjacent edge of the bottom panel, a flap hingedly connected to the side wall along a portion of its end edge, a tab receiving cut formed in the blank extending inwardly in substantial alignment with the flap hinge line, such tab receiving cut merging in a second cut extending obliquely outward of the end edge of the side wall, and defining an edge portion of the flap, a third out extending inwardly of the blank substantially parallel with the flap hinge line and offset outwardly with respect thereto, to provide an end edge portion of the side wall extending outwardly beyond such flap hinge line whereby to form a tab guiding element to facilitate reception of the tab into the tab receiving cut, the second, obliquely extending cut forming an edge portion of the flap which provides, when the flap is disposed at an angle to the side wall, a flared opening between the extended side wall end edge portion and the flap edge portion adapted to receive the tab and guide it into the tab receiving cut, and a cut at a part of the tab hinge line remote from the .bottom panel, extending inwardly of the end wall, and providing a notch when the tab is folded on its hinge line, the notch being adapted to lockingly engage the flap at the outer end portion of the tab receiving cut when the blank is erected into container form.

6. A blank for a paperboard container comprising a paperboard sheet cut and scored to provide a rectangular bottom panel, an end wall panel hingedly connected to an edge of the bottom panel, a tab hingedly connected to the end wall panel, a side wall panel hingedly connected to an adjacent edge of the bottom panel, and a flap hingedly connected to the side wall along a portion of its end edge and extending along but free of an adjacent portion of the end edge of the side wall to define therewith a tab receiving opening, a portion of the end edge of the side wall being extended outwardly beyond the hinge of the flap to assist in guiding the tab into the opening and the tab being formed with a shoulder adjacent its hinge line remote from the bottom panel and adapted to lockingly engage adjacent the outer end of the opening when the blank is erected into container form.

7.A blank for a paperboard container comprising a paperboard sheet out and scored to provide a rectangular bottom panel, an end wall panel hingedly connected to an edge of the bottom panel, a side wall panel hingedly connected to an adjacent edge of the bottom panel, a tab hingedly connected to an end edge of the end wall panel, a flap hingedly connected to the adjacent end edge of the side wall panel at a portion thereof spaced from the side wall panel hinge line, and a tab-receiving opening provided by a non-rectilinear out having at least a portion thereof extending outwardly of the flap hinge line between the flap hinge line and the side wall panel hinge line, said out defining a portion of the side wall panel end edge projecting outwardly of the folded flap to assist in guiding the tab into the opening when the blank is erected into container form.

8. A blank for a paperboard container comprising a paperboard sheet cut and scored to provide a rectangular bottom panel, an end wall jacent end edge of the side wall panel at a. portion thereof spaced from the hinge line of the side wall panel, and a non-rectilinear cut defining a portion of the side wall end edge and having two spaced points in alignment with the flap hinge line and an intermediate point located outwardly of the flap hinge line, said out extending between the side wall and a portion of the flap, whereby upon folding of the fla in erecting thecontainer a tab-receiving opening is provided between the flap and the side Wall and an end edge portion of the side wall extends outwardly of the folded flap to assist in guiding the tab into the housing.

9. A blank for a paperboard container comprising a paperboard sheet cut and scored to provide a rectangular bottom panel, an end Wall panel hingedly connected to an edge of the bottom panel, a side wall panel hingedly connected to an adjacent edge of the bottom panel, a tab hingedly connected to an end edge of the end wall panel, a flap hingedly connected to the adjacent end edge of the side wall panel at a portion thereof spaced from the side wall panel hinge line, a tab-receiving opening provided by a non-rectilinear out having at least a portion thereof extending outwardly of the flap hinge line between the fiap hinge line and the side wall panel hinge line, said out defining a portion of the side wall panel and edge projecting outwardly of the folded flap to assist in guiding the tab into the opening when the blank is erected into container form, and means for maintaining the tab in the opening tolock the walls together.

10. A blank for a paperboard container comprising a paperboard sheet cut and scored to provide a rectangular bottom panel, an end wall panel and a side wall panel hingedly connected to adjacent edges of the bottom panel, a tab hingedly connected to an end edge of the end wall panel, a flap hingedly connected to the adjacent end edge of the side wall panel at a portion thereof spaced from the hinge line of the side wall panel, a non-rectilinear cut defining a portion of the side wall end edge and having two spaced points in alignment with the flap hinge line and an intermediate point located outwardly of the flap hinge line, said out extending between the side wall and a portion of the flap, whereby upon folding of the flap in erecting the container a tab-receiving opening is provided between the ilap and the side wall and an end edge portion of the side wall extends outwardly of the folded flap to assist in guiding the tab into the opening, and means for maintaining the tab in the slit to lock the walls together.

RALPH E. ACKER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 690,498 Webb Jan. 7, 1902 1,103,708 Thumb July 14, 1914 1,470,141 Bryson Oct. 9, 1923 2,362,942 Spalding Nov. 14, 1944 2,445,034 Moore July 13, 1948 2,472,516 Buttery June 7, 1949 2,481,288 Cage Sept, 6, 1949 

